The present invention relates to a video display apparatus and method for use with, for example, a color television receiver or a multiscan computer monitor.
Currently there are computer monitors and television receivers which in addition to displaying an input video signal can display various monitor parameters that can be adjusted by displaying characters, numerals, graphics or a combination thereof. This capability to display the parameters to be adjusted is called "on-screen display" (hereinafter "OSD").
These video display devices having OSD capability are designed to allow the user to adjust parameters related to the video display operation. These parameters include the size and center position of the picture screen (raster) displayed upon under-scanning, the rotational distortion and the pincushion distortion of the screen resulting from geomagnetism, convergence, brightness, contrast and other parameters.
Such parameters are digitally adjusted by using operation keys for controlling the adjustment amount of the parameters. When these operation keys are used, graphs representing the current adjustments of the parameters are displayed and changed to reflect the new settings on the OSD portion of the display screen, thereby giving the user a visual feedback.
When the user adjusts the parameters, data indicating the adjusted amount is stored in a nonvolatile memory so that when the power supply is cycled the last adjusted parameters can be retrieved.
When parameters are adjusted as described above, a reference adjustment position for the parameter is not available. This lack of reference position creates a problem for the user by making it difficult to judge whether the current adjustment amount is proper or is too large or too small. Therefore, the user is forced to adjust the elements based on only a visual feedback of the screen leading to misadjustment and potential frustration of the user.